1. The Field of the Invention
The present invention relates generally to sonar devices and, more particularly, the invention relates to a sonar device having a sonar transducer submerged in water extending from an arm supporting the transducer.
2. Description of Related Art
Over the last several decades, commercial and recreational fishermen alike have sought more effective tools to find and catch fish. One of the most effective tools to date has been sonar depth finder units. These units provide fishermen with a virtual picture of a local underwater environment. This picture, allows fishermen to determine if fish are actually present in the area, but perhaps more effectively, it allows fishermen to locate underwater structures where fish are known to congregate. As a result, fishermen may selectively fish over such areas thereby increasing their odds of success.
Generally, fish finding units consist of a sonar display, a base for mounting the display, a sonar transducer, and an electrically conductive cable for electrically connecting the transducer to the sonar display. During use, the sonar transducer transmits ultrasonic signals that travel outwardly in a cone-shaped pattern, until striking the bottom of the body of water, submerged structures, or the fish themselves. Upon striking any of these objects, the ultrasonic signals are reflected, thereby creating echo signals that are received by the transducer. These signals are electrically transmitted to the display, which converts the echo signals into electronic signals. The electronic signals are used by the display to generate a visual representation of the local underwater environment.
Conventionally, the fish finding units described above are mounted on fishing boats and are powered by the boat's onboard power source. The unit's transducers are generally mounted to the transom or hull of the boat. In many circumstances, however, the use of a sonar fish finder may be desired in environments that are not conducive to fishing from a boat. For example, fishermen may require use of a sonar depth finder when fishing in shallow channels, along river banks, from piers or when ice fishing. Accordingly, fish finding units operated in these environments cannot rely on a boat for power or structural support. In particular, such units must be mobile, self-contained, and capable of transmitting a directed sonar signal.
In response, mobile fishing depth finder units have been developed according to the known prior art. Specifically, conventional mobile units have developed for use in ice fishing applications. These mobile ice fishing units consist of a sonar display, a base for mounting the display, a sonar transducer, a local energy source and an electrically conductive cable for mechanically supporting and electrically connecting the transducer to the sonar display. During fishing, the display is mounted to the base and positioned on a body of ice adjacent an ice fishing hole. The sonar transducer is placed within the hole such that the transducer is supported by the conductive cable below the ice. Accordingly, a “plumb-bob” configuration is produced wherein gravity acts to straighten the support cable thereby positioning the transducer substantially below the ice fishing hole.
As conventional units are used more frequently, it has become apparent that they possess a number of significant drawbacks. For example, conventional units do not operate effectively in moving water. In particular, when a plumb-bob type transducer is deposited within a rapidly moving stream or provided in a body of water having underwater currents, the transducer is deflected off-line. As described above, it is important for an effective fisherman to know the location and orientation of the sonar transducer. This information allows the fisherman to ensure that the visual information provided by the sonar display, actually represents the targeted local underwater environment. Thus, if a transducer is deflected off-line by an underwater current or other similar body of moving water, the fish finding unit is left to undesirably describe an area that has not been targeted by the fisherman. Also, the fisherman is left largely unaware that the fish finder is not displaying the intended viewing area.
Accordingly, it is desirable then to produce a fish finder unit having a transducer, which is securely supported in a known operating position either in standing or flowing water. Further, it is desirable to produce fish finder unit that is compact, mobile and easy to use. Finally, it is desirable to produce a fish finder unit having a transducer that may be quickly and easily deployed into a preferred viewing area beneath the water.